After installing ARCH Linux on a Asus EEE PC R252B I noticed that sometimes the Keyboard stops working during OS startup. (Keyboard works propperly in BIOS)
fix for kernel cmdline
I was able to fix that by adding the following to /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet i8042.reset i8042.nomux" GRUB_CMDLINE_LINUX="i8042.reset i8042.nomux"
These two options should disable the check for an active multiplexing controller and reset the controller during init.
more detailed documentation can be found at https://www.kernel.org/doc/Documentation/kernel-parameters.txt